The present invention relates to improved processes applying adhesive to thin film webs.
Three-dimensional sheet materials which include a thin layer of pressure-sensitive adhesive protected from inadvertent contact, as well as methods and apparatus for manufacturing them, have been developed and are described in detail in U.S. Pat. Nos. 5,662,758, issued Sep. 2, 1997 to Hamilton and McGuire, entitled xe2x80x9cComposite Material Releasably Sealable to a Target Surface When Pressed Thereagainst and Method of Makingxe2x80x9d; 5,871,607, issued Feb. 16, 1999 to Hamilton and McGuire, entitled xe2x80x9cMaterial Having A Substance Protected by Deformable Standoffs and Method of Makingxe2x80x9d; 5,965,235, issued Oct. 12, 1999, in the names of McGuire, Tweddell, and Hamilton, entitled xe2x80x9cThree-Dimensional, Nesting-Resistant Sheet Materials and Method and Apparatus for Making Samexe2x80x9d; and 6,194,062, issued Feb. 27, 2001, in the names of Hamilton and McGuire, entitled xe2x80x9cImproved Storage Wrap Materialsxe2x80x9d. A high speed process for making such materials is described in U.S. Pat. No. 6,163,918, issued on Feb. 27, 2001, in the names of McGuire and Bush.
The processes and equipment for manufacturing such materials described in these patents are suitable for manufacturing such materials, but are either inherently rate limited or are inefficient processes for use on a large production scale. The process described in U.S. Pat. No. 6,163,918 successfully can make the taught product, however problems occur where the adhesive does not release completely from the female embossing roll over an extended run of production. This problem of incomplete transfer may occur due to problems of material incompatibility or the wearing out of previously compatible material. This results in gradual build-up of adhesive on the roll which in turn result in misplaced adhesive on the material web or worse, the failure of the web from releasing from the transfer roll. The speed at which such processes and apparatus can be operated is a major factor in the economics of producing such materials on a commercial scale.
Accordingly, it would be desirable to provide a process and apparatus suitable for forming such three-dimensional sheet materials and applying adhesive at high speed where the release of the adhesive from the printing roll is improved.
The present invention provides a process comprising the steps of a) applying less than about 0.25 gsm of a release agent to a transfer surface, wherein the release agent is selected such that a test sample of the release agent having a concentration at or above its critical surface tension concentration, has a surface tension of less than about 50 dynes/cm or forms a contact angle with the material of the transfer surface of less than about 120xc2x0; b) applying an adhesive to the transfer surface; and c) transferring the adhesive from the transfer surface to a material web. Preferred embodiments are provided where the transfer surface is made from a material selected from the group consisting of metals, polymers, elastomers, ceramics, or wood, or combinations thereof and the release agent has the formula:
Xxe2x80x94CF2Oxe2x80x94(C2F4O)pxe2x80x94(CF2O)qxe2x80x94CF2xe2x80x94X. 
Additional embodiments are provided to continuous and intermittent processes.